Trace levels of anesthetics released during operations are potential health hazards for operating room personnel. The common anesthetic agents, halothane, enflurane, and nitrous oxide, can be metabolized in vivo or converted to more reactive compounds in vitro. Ultraviolet light irradiation is used in some operating rooms in the U.S. to decrease intraoperative infections. Ultraviolet light irradiation may decompose these agents to toxicants either directly or indirectly through ozone, singlet oxygen or other photochemical reactions. To investigate the potential role of photochemical reactions on the occupational hazards of inhalation of trace concentrations of these agents by operating room personnel rats and mice will be exposed to known concentrations of halothane, enflurane or nitrous oxide with and without light irradiation. The wavelength of the light source will be varied to determine the nature of the photochemical reaction using fluorescent, germicidal and ultraviolet lamps. The concentration of the anesthetic agent before and after irradiation will be measured by electron capture gas liquid chromatography and mass spectrometry. The nature of the decomposition product(s) will be determined and the inhalation toxicity of the irradiated gases will be determined. Conversion of nitrous oxide to nitrogen dioxie and other oxides of nitrogen will be determined chemically. Finally the concentration of the anesthetic agents and their potential toxic decomposition products will be measured in the operating room. These data will be used to assess the potential human hazards from long term occupational exposure.